Sentinel Pine Covered Bridge - Located in New Hampshire’s Franconia Notch State Park is the picturesque Sentinel Pine Covered Bridge. Built by the Society for the Protection of New Hampshire Forests in 1939, the roughly 60 foot long covered bridge crosses the Pemigewasset River just above a natural basin knonw as "The Pool”. The covered bridge is named for a massive old white pine tree that once stood on the cliff above the pool; it watched over the pool much ...